The invention relates to a packaging tube.
Packaging tubes are know, in which the tube body and the head portion comprise plastic material. The tube bodies are either extruded or are produced by rolling and overlappingly joining a single-layer plastic foil in endless form, to constitute a tube member (plastic tubes).The tube is cut into portions of the desired lengths to form the tube bodies and the tube bodies are provided at one end with a head portion to close the tube body. For the purposes of providing a tube body with a head portion, it is known to prefabricate head portions and to join them to the tube body by fusing them thereto. A further possible procedure is that of injection or press moulding the head portion,in which case the tube body is also joined to the head portion by being fused thereto, during the operation of forming the head portion. In regard to the plastic materials for the production of extruded tubes and the foils for making the rolled tubes,only plastic materials of such a composition or plastic material mixtures such that their melting characteristics are to be matched to the melting characteristics of the plastic materials of the head portions are to be used. It is due to the permeability of the plastic materials that tubes of those materials are not suitable for packaging materials with volatile, for example flavouring components,as the latter diffuse through the tube body and the head portion. Likewise the use thereof for the packaging of oils and greases is restricted.
For packaging materials which involve high levels of requirement, in the areas of foodstuffs, pharmaceuticals or hygiene matters, tubes with diffusion barriers have been developed to provide for protection in regard to flavouring or active substances, in respect of the packaging tubes. The tube bodies of such tubes are made from an aluminium-plastic laminate (metal-laminate tubes), for example an aluminium foil which is lined with plastic material on both sides and which forms the diffusion barrier after rolling and welding of the plastic layers. In order to eliminate the possibility of diffusion through the head portion, it is known for a covering of the same material as the tube body to be provided on the outer or inner surface of the head portion. Metal-laminate tubes of that kind provide reliable protection in regard to flavouring or active substance and the methods of manufacture thereof have attained a high technical status.
In contrast to plastic tubes, metal-laminate tubes are not readily recyclable. While plastic tubes can be re-processed to provide raw material again, by means of simple processes and without involving substantial losses of material, in the case of metal-laminate tubes two materials, namely the plastic material and the aluminium, first have to be separated from each other and processed separately. Melting down the plastic material, and its individual processing as well as melting the metal, are expensive and time-consuming operations. That expenditure on re-cycling is found to be a disadvantage with metal-laminate tubes.